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118 - 165 IP Telephony v1.0 Lab 7.1.1 Copyright © 2005, Cisco Systems, Inc.
• Configure the command to implement AutoQoS for VoIP
• Examine the results of implementing AutoQoS for VoIP
Step 1 Verify Connectivity and IP Phones
a. This lab requires that two pods be used and both pods are functional. Ensure that an IP phone
from one pod can call an IP phone on the other pod.
b. Does the phone call work from one pod to the other? If not, perform appropriate troubleshooting.
__________
c. Have one pod partner slowly count from one to 10 while one or two phone connections are
made.
d. How is the voice quality? _______________________________________________________
e. From the lowest numbered pod router, do an extended ping to the other router with a packet size
of 1500 bytes. Refer to IP Telephony Table 1 for a list of IP addresses
CMERouterX# ping
Protocol [ip]: <Enter>
Target IP address: <ip_address>
Repeat count [5]: 1000
Datagram size [100]: 15000
Timeout in seconds [2]: <Enter>
Extended commands [n]: <Enter>
While the ping is occurring, place at least one phone call from one pod to another. Multiple calls
can be made. Have one pod partner slowly count from one to 10 while the phone connection is
active.
f. How is the voice quality? ______________________________________________________
g. Stop the ping by pressing CTRL+Shift+6 or wait for the ping to finish.
h. Display and examine the running configuration of the CME router.
Step 2 Configuring AutoQoS on Cisco IOS Routers
a. Set the clock rate on the DCE serial link between the two router pods to 72000.
CMERouterX(config-if)# clock rate 72000
b. On both CME routers in dial peer configuration mode, set the codec to the G.711 u-law
(pronounced myoo (like the greek leter) law) standard. Codec stands for coder/decoder. The
defined codec is the set of rules for converting analog signals to digital and vice versa. The two
main types of codecs used are G.711 and G.729. G.711 encodes audio on a 64kbps channel.
G.729 encodes audio on a 8kbps channel. G.711 and G.729 come in two different types: a-law
and u-law. A-law is used with international circuits and u-law is used with U.S. circuits.
CMERouterX(config)# dial-peer voice 6 voip
(CMERouterX(config-dial-peer)# codec g711ulaw
c. From the lowest numbered pod router, do an extended ping to the other router with a packet size
of 1500 bytes. Refer to IP Telephony Table 1 for a list of IP addresses
CMERouterX# ping
Protocol [ip]: <Enter>